You can use msconfig: Start -> Run -> "msconfig"
There is a part of that program that allows you to configure which programs are running. (check the "startup" tab)

If you feel like being really "technical", you can also disable/enable programs by editing your registry directly. Run "regedit", browse to HKeyLocalMachine/Software/Microsoft/Windows/CurrectVersion/Run and you can edit/delete any keys for programs you don't want.

By the way, quicktime would be "qttask.exe". And feel free to disable it.